Portable computers (e.g., laptop, handheld and subcompacts) achieve their small overall size and volume by folding their largest component, their display screen and supporting lid subassembly, when not in use. Unfortunately, hinging the display subsection makes it difficult to communicate with or power devices in the lid portion. This occurs because the wires used to connect devices in the lid with devices in the base must often snake within the hinge itself and are exposed to constant bending and unbending. Further, connections to devices in the lid (e.g., LCD graphic displays, USB cameras and other devices) may require many signal wires which must be compressed into a tiny area of the hinge width. Compressing these wires into a small area requires small signal trace sizes which in turn creates problems of signal cross-talk between traces and other types of interference.
The problem is exacerbated when wireless local area network (WLAN) and wireless wide area network (WWAN) connectivity is added to these types of portable computers. WLAN and WWAN employ radio technologies and each require the inclusion of specialized antennas that work best when positioned in the highest location possible within a unit, usually the lid area of the portable computer. The interconnects required between the motherboard of the portable computer and a WLAN and/or WWAN radio subsystem located in its lid further complicate the hinge wiring problem by adding more signals with higher data rates. In addition, marketing requirements may dictate that all parts of a portable computer system be as thin as possible. Therefore, the wiring system elements (e.g., flexible circuits, connectors, shielding and wires) may ultimately limit the marketability of a particular portable computer by limiting the thickness of the lid or in some cases even the main case itself. Even if the hinge wiring harness is enlarged to include WLAN or WWAN (or both) radio interface signals, the signals may interfere or be interfered with by the other signals such as for the LCD display.
Finally, the cost of the wiring system elements for the various subsystems in a portable computer is non-trivial. It has been found that only specialized flexible circuit substrates are able to carry the required number of signal lines with the flexibility and durability needed in the demanding environment of the hinge area. Such wiring subassemblies are costly to build and to assemble within the body of the computer case itself. Further, wiring subsystems subject to movement (folding, sliding, etc.) are a major contributor to original equipment manufacturer (OEM) customer service costs due to increased calls and product returns. To enable modern portable computer systems to continue to add desired technologies and to retain their marketable physical size and weight, there is a need for a way to reduce the wiring required for communicating signals between devices in the main body and devices in the lid of portable computer systems.